Descartes' Mechanics

The Prince of Orange successfully ended the campaign for the States with the capture of Breda.

• He returned to The Hague to spend the winter there.

Descartes took this opportunity of Mr. de Zuytlichem’s rest to send him the short treatise on Mechanics that he had composed at his request almost 2 years earlier when he was in Friesland.

This writing was only an imperfect memo of what had come to his mind on what his friend demanded of him.

it was a notebook where he had thrown down without much order what he believed to be precisely the most necessary: and one can say that the fear of getting involved in a regular and of a just length treatise, had made him purposely omit what there is most beautiful in Mechanics.

This consideration made him unable to bear that Mr. de Zuytlichem made so much of it: and to respond to all the politenesses that this one used to thank him for it, he was content to tell him that the “three sheets” that made up his treatise “were not worth” together “the least of the words” of his thanks.

He had so much abandoned the property of it to him that he did not intend that he should ever return it to him, or even that he should have copies taken of it for others. But this cession was without him thinking about it a permission to Mr. de Zuytlichem to use it as his own, according as he would judge it appropriate, and to communicate it to whomever he saw fit.

He used his right but with his permission a short time after with regard to Mr. De Pollot who frequented the court of the Prince of Orange and that of the Queen of Bohemia in The Hague, and whom he knew besides to be the particular friend of Mr. Descartes, and to render him very good services in all the occasions that met. Mr. Descartes wrote to Mr. De Pollot to assure him that he found nothing to say against it.

For the little writing on mechanics, he said, that I sent a short time ago to Mr. de Zuytlichem, I have reserved no power over it. So as I could only find it very good that he communicates it to you, if it pleases him; so I could not find it bad that he abstains from it for the shame I have that a writing so imperfect from me is seen.

These sentiments make it known enough how far he would have been from suffering that this writing would ever be printed; and it is credible that neither Mr. de Zuytlichem, nor Mr. de Pollot, nor any other of his friends would have resolved to render him this bad service after his death, if he had acquitted in his lifetime the word that he had given them to work on a complete and regular treatise on mechanics. But Sieur Borel finding himself in Holland after his death, and having recovered a copy of the imperfect writing that Mr. de Zuytlichem and Mr. de Pollot had had, did not have any difficulty in giving it with two letters addressed to Princess Elizabeth to put them under the press. This writing that connoisseurs estimate to be comparable to the biggest works of mechanics, was printed in Paris in the year 1668 In IV with that of music by the care of Father Poisson of the Oratory.

However, in order not to omit inappropriately what can serve as a response to those who would now want regard to be had for the imperfections of this treatise, it is necessary to warn them that the fear that Mr. Descartes had of getting involved in a treatise that was much longer than Mr. de Zuytlichem had asked for, has been the cause that he has omitted “the most beautiful of his subject as among other things, 1 the consideration of speed, 2 the difficulties of the balance, 3 and several means that one can have to increase the force of the movements that differ from those he has explained.” Thus it is on his laziness rather than on the ignorance of his subject that “those who will want to make his trial should judge him.”

Mr. de Zuytlichem to whom the public has the first obligation for this work was still in the mourning he had taken for the death of his wife, who had passed away as early as April of the year 1637. This lady’s name was Susanne De Baerle, and she was mourned by all the friends of Mr. de Zuytlichem, that is to say, by an infinity of people of note spread throughout Europe. They were tears due to her particular merit rather than to the pain of her husband.

She had not been content with giving him children who have worthily supported the dignity and the name of their family by their excellent qualities, she had also distinguished herself by an irreproachable conduct and by all that can form the reputation of a person of honor. She had besides that knowledge that elevated her above the common of her sex: and what is more, she was a witty person. She knew how to write seriously, and to joke pleasantly in prose and in Latin verse. She had taken pleasure in exercising herself among others against the poet Barlaeus because of the meeting of his surname with hers: and they sent each other verses with a very great freedom of style to be sure, but always innocent on the side of Madame De Zuytlichem, who one day wanting to reproach him for his timidity, put at the head of the piece she addressed to him Susanna Barlaeus Gaspari Barlaeae. Mr. Descartes had been very sensitive to the loss that Mr. de Zuytlichem had made of a woman of this merit, and he had acquitted himself early of the duties that their mutual friendship prescribed to him. He had written him a letter of consolation as early as May that he had only filled with the maxims of philosophy, to remind his friend that he should not be less of a philosopher on this occasion than in the other accidents of life.

Zuytlichem had always hoped that Balzac would not fail him in this meeting.

But 1637 passed without him receiving anything from him, and without even hearing him spoken of.

He complained about it to Descartes as to a common friend, capable of “avenging him of Mr. de Balzac’s negligence, or of inventing reasons proper to excuse him.”

Descartes took this second side in the response he made to Mr. de Zuytlichem. He wanted to make him believe that Mr. de Balzac, a lover as he was of freedom, had undoubtedly not been able to persuade himself that there were ties in the world that were so sweet, that one could not be delivered from them without regretting them. But that besides that he was one of the most constant in his friendships, even if he was not always one of the most diligent in making it known by his letters.

Descartes and Zuytlichem made in that year the loss of another common friend, who was Laurent Realius or Mr. Reael. He had had the first jobs on the fleet and in the Indies for the Dutch. He passed for the first man of the century in “magnetic philosophy and neither Gilbert nor Cabeus had anything to teach him on this subject.” He possessed navigation perfectly, and he was barely less versed in the rest of mathematics.

However, the reading of Mr. Descartes’s book was beginning to produce its effects according to the different disposition of minds. There were few things in all that he had written, that did not appear doubtful for some and new for others. The true learned men were not frightened by what was new, and which could only make Mr. Descartes odious to those who were stubborn with their prejudices: but they took occasion from what appeared doubtful to them, to prepare to make him objections according as he had made them testify that he wished it to procure greater clarifications to the truth.

Mr. Mydorge his friend would have been one of the most proper for this, if he had not already found himself in advance of the same sentiment as him in several things as early as the time they saw each other in Paris. He could have at least proposed to him difficulties on various places of the sixth discourse of dioptrics, where Mr. Descartes treats of vision in a way different from that in which he had the habit of explaining this matter himself. But he was content to speak of it to Father Mersenne, who did not delay in writing to Mr. Descartes; and to testify to him that Mr. Mydorge having read his geometry would have wished to see his old algebra “to facilitate the intelligence of some places that he found obscure in the second book of geometry.” Mr. Descartes responded to Father Mersenne on both points. I do not find it strange, he told him, that Mr. Mydorge does not agree with me in several things of what I write about vision.

For it is a matter that he has formerly studied a lot: and not having followed the same principles as me, he must have taken other opinions. But I hope that the more he examines my reasons, the more they will satisfy him: and he has too good a mind not to surrender to the side of truth. I would have no difficulty in sending him my old algebra, if it was worth the trouble. It is a writing that does not seem to me to deserve to be seen: and because there is no one, that I know of, who has a copy of it, I will be very happy that it no longer leaves my hands. But if he wants to take the trouble to examine the third book of my geometry, I hope that he will find it easy enough, and that he will then easily succeed in the second.

Mydorge followed this advice.

• He did not find himself badly off.

He had no more objections to make to his friend: and far from tiring him with many others by this place, one can say that he did the Descartes in Paris, by taking charge of responding for his absent friend, to the objections that one did not want to send to Holland.

He was not the only one in Paris who studied to render him good offices. Mr. Des Argues of whom we have already had occasion to speak, forgot nothing to serve him with Cardinal de Richelieu, and to promote his inventions of dioptrics to those who approached his eminence. He addressed himself to Father Mersenne to let Mr. Descartes know the state in which he had put things, and to tell him that the cardinal had listened to the proposals that had been made to him to work on glasses on the rules that he gives in his dioptrics. Mr. Descartes wrote back to Father Mersenne to mark his distance on these resolutions. He asked him to testify to Mr. Des Argues and to the other people who were involved in this affair, that he was very obliged to them for the good opinion they had given the court of his inventions of dioptrics: but that he “did not believe that the thoughts of Mr. the cardinal should lower themselves to a person of his kind.”

It was not by a modesty of bad timing that he resisted the intentions of these Gentlemen: it was by the fear that one would not succeed badly in his absence, and that one would then reject on himself the faults of the workers. For he believed that his presence was necessary to direct the hand of the Turners, and to give them new instructions as they advanced or as they failed.

He gave notice of what was happening in Paris on this subject to Gentlemen de Zuytlichem and de Pollot. He told the first that he had every reason to hope well for the Turner he had sent him both for his skill and for his affection for work; that he would willingly go to Amsterdam expressly to see his models, and to make him understand all that there would be to observe; and that if the Turner succeeded, he would do his best with his friends in Paris to have him obtain an exclusive privilege, that only he could sell these glasses in France. However, he felt so obliged to Mr. des Argues for his good offices, and for other services that he had still rendered him since his retreat in Holland, that he had him offered all that would depend on him to recognize them: and wanting to enter from now on into commerce of letters with him, he asked Father Mersenne to tell him his qualities and his address, because not having seen each other since the siege of La Rochelle, he had not thought of informing himself of what concerned him.